Black Monday was the name used for the first major trading day of the 1987 global stock-market crash in Hong Kong. On 19 October 1987, the Hang Seng Index fell 11.1%, helping set off a worldwide wave of selling.
The decline then spread through other Asian markets and reached Europe and the United States. Hong Kong’s market was particularly vulnerable because investor confidence was already fragile and the exchange had experienced sharp volatility.
The same date became most famous for the Dow Jones Industrial Average’s 22.6% percentage plunge in New York. The term Black Monday therefore refers to a global event, not only an American crash.
Hong Kong’s exchange remained closed for several days after the initial shock. The episode later encouraged stronger coordination among exchanges and the creation of procedures for temporarily halting trading.